Doesn't look like he did it on purpose. the scene cuts to a later time midway through and you see the car flying up behind them and then hits.

It looks like he was being an idiot and speeding down the road and couldn't stop. Plus the article a few posts back says the guy had alcohol on his breath. drunk + speeding + acting like an idiot = this mess. Guy who hit them should be put behind bars, though. definitely. his driving killed a man. go directly to jail, do not pass go, do not collect $200.